Heating boiler



Nbv. 7, 1961 G. OSPELT 3,007,457

HEATING BOILER Filed Jan. 19. 1959 2 Sheets-Sheet 2 jnventan' GuJ-fa 0% s /f' RAM/24 k- United States The present invention relates to a heating boiler with a burner for liquid or gaseous fuels and a bell-shaped water jacket surrounding the combustion chamber or fire box. More specifically, the invention relates to a heating boiler of the just mentioned type which has a burner arranged at the open end of said water jacket, while the combustion gases leave said combustion chamber at said open end.

With a heretofore known arrangement of this type of heating boiler, the combustion gases, after leaving the combustion chamber, pass in axial direction along the outer surface of the water jacket. For purposes of improving the heat transfer from the combustion gases to the water jacket, rings of helical wires are put round the outer surface of the water jacket and welded thereto which bring about an increase in the heat absorbing surface.

It is an object of the present invention to provide a heating boiler which will further increase the specific thermal capacity (kilo-calories per square meter heating surface and hour).

Is is another object of this invention to provide a heating boiler of the type set forth in the preceding paragraph, which will represents a compact space and ma terial saving construction.

It is also an object of this invention to provide a heating boiler of the above mentioned type in which the heat transferred per unit surface can easily be changed in conformity with the respective requirements.

These and other objects and advantages of the invention will appear more clearly from .the following specification in connection with the accompanying drawings, in which:

FIG. 1 is a diagrammatic central axial section through a heating boiler according to the invention with a warm water producer, particularly for larger units with a pressure of approximately 50 to 100 millimeter Water column in the combustion chamber or fire box.

FIG. 2 illustrates partly in view and partly in section a modified structure of a heating boiler according to the invention, which is particularly suitable for smaller units with a pressure in the combustion chamber or fire box of approximately from 2 to 5 millimeter water column.

FIG. 3 is a cut-out of FIG. 1 on an enlarged scale.

General arrangement The heating boiler according to the present invention comprises a burner for liquid or gaseous fuels, a combustion chamber or fire box surrounded by a bell-shaped water jacket, an annular passage surrounding said water jacket for the discharge of the combustion gases, and a wall covering said annular passage and the open end of the com-bustion chamber while leaving a communication between the combustion chamber and said annular pas sage. Freely longitudinally displaceable in said annular passage there is arranged a helical surface guiding wall which has a height approximately corresponding to the radial width of the annular passage, at least that portion of the said helical surface guiding wall which covers said annular passage and contains the burner being designed as a detachable lid. The said burner is arranged substantially along the axis of the combustion chamber in the said well which leaves a communication between the combustion chamber and the annular passage. The

atent C above outlined construction considerably increases the path along which the flue or Waste gases have to pass along the outer surface of the bell-shaped water jacket. It is a matter of course that at the same time the flow velocity has to be increased corresponding to the de creased cross section of the helical discharge passage by correspondingly increasing the drop of pressure. The heat transfer to the water in the boiler in considerably aided by a high velocity and by turbulence of the combustion gases in said passage. Practical tests have proved that with the arrangement according to the invention, surprisingly, a multiple of the heretofore possible specific thermal capacity can be obtained, which fact results in a considerable reduction and improvement of the heating boiler. It is particularly advantageous to surround the annular passage by a Water chamber communicating with the bell-shaped water jacket, because in such an instance the increased heat transfer Will occur on the inner surface as well as on the outer surface of the helical passage. Preferably, also the bottom of the bell-shaped water jacket will be arranged in spaced relationship with regard to the water chamber and be surrounded by the latter while the discharge connection for the combustion gases is arranged for communication with the thus formed intermediate chamber. In this way, also at this point an improvement in the specific thermal capacity will be obtained.

During their course, the combustion gases will be cooled in the boiler to about 200 C. whereby, of course, the temperature difference with regard to the boiler water will be continuously changed. In other words, the combustion gases will during their flow through the boiler (boiler meaning the entire structure, ie the water as well as the waste gas conducting parts) cool off to about 200 C. by conveying their heat to the water. The water in the boiler, however, has everywhere a temperature below C. The difference between the temperature of the gases and the temperature of the water will thus vary at the individual points where the heat is conveyed from the gases to the water. On the inside of the bell-shaped water jacket, the gases are hotter than in the waste gas passage between the helical surface guiding walls so that also the temperature difference between the interior of the water jacket and the water is higher than the temperature difference between the Waste gas passage and the water. and the decrease in the gas velocity caused by the cooling off of the gas, the heat transfer will at constant cross section of the helical passage be less at the end'than at the start. In order to obtain a uniform heat transfer throughout the entire length of the passage, according to a further feature of the invention the pitch of the helical surface guiding wall may be continuously decreased in the direction of the discharging flow of the combustion gases. Expediently, this is effected to such an extent that the speed of the combustion gases will at least approximately remain constant.

Inasmuch as the purpose of the helical surf-ace guiding wall is not to provide a heat exchange surface, this helical surface guiding wall may be arranged with play in the annular passage surrounding the bell-shaped water jacket. Such an arrangement makes it possible, after removal of the lid covering the annular passage, to withdraw the guiding wall as an entirety or unit for purposes of cleaning the same. This fact that the guiding wall may be Withdrawn, is of foremost importance for the boiler efficiency because a good heat transfer is possible only when the unavoidable soot deposit can be removed from time to time without difiiculty. In order, preferably for this purpose, to make the helical surface guiding wall in its entirety a rigid structure, it may be connected to Du to the decreasing temperature longitudinal bars extending axially over the entire length of the guiding wall. In view of this connection, the helical surface guiding wall can easily be exchanged, for instance for a helical surface guiding wall of less pitch and more windings, in other Words, for a guiding wall with a longer path for the waste gases. In this way, the heating boiler can easily be transformed into one for a different specific thermal capacity, which fact is highly advantageous with regard to the manufacture and storing of boilers of the type involved.

For the sake of completeness it may be added that it is known to discharge fine gases through an annular passage having a spiral shaped guiding wall. However, with this known arrangement the annular passage is provided with radial ribs fixedly connected to the wall of the annular passage and provided with helical slits holding the helical guiding wall so that the latter is fixed and stationary and cannot be displaced longitudinally so that it cannot be removed from the annular passage.

It may also be added that a bell-shaped water jacket is known in connection with heating boilers which has an annular passage without a helical guiding wall so that the gases pass along the axis of the bell-shaped water jacket on the outside thereof. With this known arrangement, wire spirals are arranged in the annular passage and extend around the bell-shaped water jacket, one spiral being located adjacent the other. The gases have to wind their way through said spirals so as to convey the heat thereto, and the spirals convey their heat to the wall of the Water jacket. In this arrangement the said spirals slow down the axial passage of the waste gases, whereas in contrast thereto in applicants arrangement the waste gases are passed around the water jacket at high speed through a helical path and at said high speed move over a long path before leaving the boiler.

Structural arrangement Referring now to the drawings in detail, the heating boiler shown therein comprises a bell-shaped water jacket 2 and a water chamber 1. The outer Wall of water chamber 1 is formed by a cylindrical wall 3, a bottom 4, and a concave lid 5. The inner wall consists of a cylindrical insert 6 which is arranged perpendicularly to the vertical axis of the cylindrical wall 3. The insert 6 extends on one side through the cylindrical wall 3 and communicates at the axially opposite side with a connection 7 which in turn leads to the flue. The bellshaped waterjacket 2 is spaced on all sides from and arranged coaxially in the interior of the cylindrical insert 6. An oil burner 8 of the high pressure type is provided with a corresponding fan 10 and while likewise being coaxially arranged extends into the interior of the Water jacket 2, the inner wall of which thus forms the combustion chamber or fire box 9. Oil burner 8 and fan 10 are connected to a lid 11 which for instance by means of a ceramic plate 12 may be heat insulated and closes the cylindrical insert 6 with regard to the outside. The flame of the burner will have a shape substantially equalling that illustrated in the drawing. As will be seen from the drawing, the flame is directed against the double bottom 13 of the bell-shaped water jacket 2. The heat transfer in the interior will thus be effected primarily by radiation. The combustion gases will flow along the path indicated by the arrows 14 and 15, which means that they will be deviated twice by 180 so that the combustion gases will pass into the annular chamber 16 between the water jacket 2 and the Water chamber 1 and will fiow on from here along the bottom portion 17, as indicated by the arrows 18, into the discharge connection 7 communicating with the flue. To this end, between the water jacket 2 and the insulating plate 12, there is provided a disc-shaped intermediate chamber 16' serving as deviating chamber. Arranged in the annular chamber 16 is a screw-shaped or helical surface guiding wall 19 which after removal of lid 11 can be inserted into passage 16, said lid being detachably connected to the water chamber 1 in any convenient manner, for instance by screws 50. The helical surface guiding wall 19 forms a helical passage 26 which must be passed through along its length by the waste gases as indicated by the arrows 21. The Waste gases pass simultaneously at high speed along the water jacket 2 and that Wall of water chamber 1 which is adjacent the annular chamber 16, while turbulence will form so that all conditions will be present for a best possible heat transfer from the combustion gases to the boiler water. For purposes of holding the individual windings of the helical surface guiding wall 19 stationary with regard to each other, axially extending threaded longitudinal bars 22 are provided which extend through bores in the guiding wall. The individual windings of the guiding wall are by means of pairs of nuts 23 (FIG. 3) held in their respective positions on bars 22. In this way, a rigid insert is obtained which can easily be withdrawn as a single unit. The helical surface guiding wall is loosely and with slight play arranged in the annular passage 16. It is not necessary to have a gap everywhere along the inner and outer periphery of said guiding wall, but said guiding wall may rest either on the upper portion of the bell-shaped water jacket 2 or it may rest on the lower portion of the cylindrical insert 6. If necessary, the spacing of the individual windings of the helical surface guiding wall may decrease in the direction of flow of the waste gases in order to obtain the best heat transfer conditions in all parts of the passage 20. This decrease in the spacing of the individual windings is clearly shown in FIG. 1 where the spacing of the two last windings of the helical surface wall (see bottom portion thereof) is noticeably less than the spacing of the helical surface winding walls on the left-hand side of FIG. 1. Also FIG. 2 brings out the above mentioned decrease in the spacing of the helical surface winding walls toward the connection 7.

The water chamber of water jacket 2 communicates through a connection 24 with the water chamber 1, said connection 24 being arranged approximately at the lowest point. The water jacket 2 the lower portion of which is for the most part separated from the upper portion by lateral walls 25 is entered by the water at the lower portion thereof. While the lateral walls 25 are not necessary for the proper functioning of the boiler according to the present invention, they have some beneficial effect. The said walls 25 which are located in the water jacket 2, bring about a certain circulation of the Water in water jacket 2. The purpose of walls 25 consists in preventing the water entering through connection 24 from too early rising and leaving through pipe 27. In other words, walls 25 are intended to force the water entering through connection 24 to flow to the front end of the bell-shaped water jacket 2, then to flow around the guiding walls 25 and backwards to the discharge pipe 27. Expressed differently as indicated by the arrows 26, the water is forced to pass into the upper portion of water jacket 2 at that end thereof which is located opposite the connection 24 and to be discharged at the back side through pipe 27 extending into the boiler 28 for usable water, said boiler being mounted on lid 5 and serving as warm water producer. The upper portion of boiler 28 is provided with two bottoms 29 and 30 forming a distributing chamber 31 for the hot water. A heat exchange is effected through the intervention of a number of pipes 32 connecting the distributing chamber 31 with the water chamber 1. The hot water is fed through the above mentioned pipe 27 which is located with play 36 Within a pipe 33 likewise establishing communication between the distributing chamber 31 and the water chamber 1. As will be seen from the drawing, pipe 27 extends closely to the distributing chamber 31. If the usable water has not yet reached its maximum temperature, the water circulation is effected as indicated by the arrows 34 and 35. As soon as boiler 28 has been heated up completely, the

said water circulation effected by a .thermo-siphon effect will naturally come to a stop, whereupon the water heated in the bell-shaped waterjacket 2 will flow through pipe 27 and passage 36 of pipe 33 into the water chamber 1. In case of high heat consumption of the boiler for the usable water it is also possible that hot water flows from the water chamber 1 through passage 36 to the distributing chamber 31 and heating pipes 32 additionally to the hot water coming from pipe 27. The water cham her 1 is furthermore provided with a feeding connection 37 and return connection 3,8. The reference numeral 39 designates the cold water inlet, whereas the reference numeral 40 designates the discharge connection for warm water of the usable water of boiler 28. Distributing chamber 31 is connected to an expansion vessel through connection 41. The numeral .42 designates an insulating cover surrounding the entire heating boiler.

With the heating boiler shown in FIG. 2, the bellshaped water jacket 2 extends up to the ceramic plate 12 of lid 11. For purposes of effecting a communication between the combustion chamber or fire box 9 and the annular passage 16, the bell-shaped Water jacket 2 is cut out within the range of the first portion of the waste gas passage formed by the helical'surface guiding wall 19. The combustion chamber or fire box 9 communicates through the thus provided cut-out 43 with the waste gas passage 20. The cut-out 43 is confined by the wall surfaces 44 and 45 of water jacket 2 and by ceramic plate 12. The development of the portion cut out from the water jacket 2 will thus in the illustrated embodiment have the shape of a triangle. The edges of surfaces 44 and 45 as developed in a plane will form two sides of this triangle. The discharge of the combustion gases from the combustion chamber or fire box 9' is effected in the manner illustrated by the arrows 46.

It is, of course, to be understood that the present invention is, by no means, limited to the particular constructions shown in the drawings but also comprises any modifications within the scope of the appended claims.

What I claim is:

1. In combination in a heating boiler: a combustion chamber having a substantially horizontal axis and an open end, a bell-shaped water jacket surrounding said combustion chamber, wall means extending around said water jacket in spaced relationship thereto and confining with said water jacket an annular passage surrounding said water jacket for withdrawal of combustion gases, said wall means also extending around said open end of said combustion chamber, a helical surface guiding wall freely and longitudinally displaceably mounted in said annular passage and having a height coresponding approximately to the radial width of said annular passage, detachable lid means normally closing said annular passage and said open end of said combustion chamber toward the outside of said boiler while leaving free a connection between said combustion chamber and said annular passage, at least part of said lid means being selectively detachable for permitting withdrawal of said helical surface guiding wall from said passage, and means for injecting fuel into said combustion chamber substantially along the longitudinal axis of said combustion chamber.

2. In combustion in a heating boiler: a combustion chamber having a substantially horizontal axis and an open end, a bell-shaped water jacket surrounding said combustion chamber, wall means extending around said water jacket in spaced relationship to said water jacket and confining therewith an annular passage surrounding said water jacket for withdrawal of combustion gases, said wall means also extending around said open end of said combustion chamber, a helical surface guiding wall freely and longitudinally displaceably mounted in said annular passage and having a height corresponding approximately to the radial width of said annular passage, detachable lid means normally closing said annular connection between said combustion chamber and said annular passage, at least part of said lid means being selectively detachable for permitting withdrawal of said helical surface guiding wall from said passage, a water chamber surrounding said wall means and communicating with said bell-shaped water jacket, and means for injecting fuel itno said combustion chamber substantially along the longitudinal axis of said combustion chamber.

3. In combination in a heating boiler: a combustion chamber having a substantially horizontal axis and an open end, a bell-shaped water jacket surrounding said combustion hamber, wall means extending around said Water jacket in spaced relationship thereto and confining with said water jacket an annular passage surrounding said water jacket for withdrawal of combustion gases, said wall means also extending around said open end of said combustion chamber, a helical surface guiding wall freely and longitudinally displaceably mounted in said annular passage and having a height corresponding approximately to the radial width of said annular passage, detachable lid means normally closing said annular passage and said open end of said combustion chamber toward the outside of said boiler while leaving free a connection between said combustion chamber and said annular passage, at least part of said lid means being selectively detachable for permitting withdrawal of said helical surface guiding wall from said passage, and fuel injecting means for injecting fuel into said combustion chamber substantially along the longitudinal axis of said combustion chamber, the pitch of said helical surface guiding wall decreasing in the axial direction thereof away from said fuel injecting means.

4-. A boiler according to claim 3, in which the decrease in the pitch of the helical surface guiding Wall away from said fuel injecting means is so selected that the speed of the combustion gases flowing along said helical surface guiding wall remains at least approximately constant.

S. In combination in a heating boiler: a combustion chamber having a substantially horizontal axis and an open end, a bell-shaped water jacket surrounding said combustion chamber, wall means extending around said water jacket in spaced relationship to said Water jacket and confining therewith an annular passage surrounding said water jacket for withdrawal of combustion gases, said Wall means also extending around said open end of said combustion chamber, a helical surface guiding wall composed of a plurality of helical wall portions, means extending over substantially the entire axial length of said helical surface guiding wall and having said helical Wall portions connected thereto so as to form a unit therewith, said helical surface guiding wall as a unit being freely and longitudinally displaceably mounted in said annular passage and having a height corresponding approximately to the radial width of said annular passage, detachable lid means normally closing said annular passage and said open end of said combustion chamber toward the outside of said boiler while leaving free a connection between said combustion chamber and said annular passage, at least part of said lid means being selectively detachable for permitting withdrawal of said helical surface guiding wall from said passage, and means for injecting fuel into said combustion chamber substantially along the longitudinal axis of said combustion chamber.

6. A boiler according to claim 5, which includes threaded bar means extending through said helical wall portions, and a plurality of pairs of nuts, each of said helical wall portions being positioned on said bar means by one of said pairs of nuts.

7. In combination in a heating boiler: a combustion chamber having a substantially horizontal axis and an open end, a bell-shaped water jacket surrounding said combustion chamber, wall means extending around said Water jacket in spaced relationship to said water jacket and confining therewith an annular passage surrounding said water jacket for Withdrawal of combustion gases, said wall means also extending around said open end of said combustion chamber, a helical surface guiding wall freely and longitudinally displaceably mounted in said annular passage and having a height corresponding approximately to the radial width of said annular passage, a water chamber surrounding said annular passage, connecting means establishing communication between said water chamber and said bell-shaped water jacket and forming a heat exchanger with a thermo-siphon effect bringing about a water circulation, detachable lid means normally closing said annular passage and said open end of said combustion chamber toward the outside of said boiler while leaving free a connection between said combustion chamber and said annular passage, at least part of said lid means being selectively detachable for permitting withdrawal of said helical surface guiding wall from said passage, and means for injecting fuel into said combustion chamber substantially along the longitudinal axis of said combustion chamber.

8. In combination in a heating boiler: a combustion chamber having a substantially horizontal axis and an open end, a bell-shaped water jacket surrounding said combustion chamber, Wall means extending around said water jacket in spaced relationship to said Water jacket and confining therewith an annular passage surrounding said water jacket for Withdrawal of combustion gases, said wall means also extending around said open end of said combustion chamber, a helical surface guiding wall freely and longitudinally displaceably mounted in said annular passage and having a height corresponding ap proximately to the radial width of said annular passage, detachable lid means normally closing said annular passage and said open end of said combustion chamber toward the outside of said boiler, one of the end portions of said bell-shaped water jacket having passage means therethrough for establishing direct communication between said combustion chamber and said annular passage, at least part of said lid means being selectively detachable for permitting withdrawal of said helical surface guiding wall from said passage, and means for injecting fuel into said combustion chamber substantially along the longitudinal axis of said combustion chamber.

References Cited in the file of this patent UNITED STATES PATENTS 544,152 De Benjumea Aug. 6, 1895 1,077,160 Reese Oct. 28, 1913 2,431,460 Burkhart Nov. 25, 1947 2,625,915 Glasgow et a1. Jan. 20, 1953 2,674,981 Clarkson Apr. 13, 1954 FOREIGN PATENTS 15,523 Norway Sept. 3, 1906 

